By Phil Black, Nick Paton Walsh and Michael Pearson
Kiev, Ukraine (CNN) - A short-lived truce crumbled Thursday as gunfire erupted at Independence Square, the center of anti-government protests and an increasingly violent crisis that threatens catastrophe for this divided nation.
The head of the protesters' medical service said 100 people died and 500 were injured in clashes on Thursday, just hours after the government declared a truce in fighting that had shocked world leaders with the deaths of 28 people two days before.
The Ukrainian government has not released its own casualty figures, but Interior Minister Vitali Zakharchenko said 25 police officers had been wounded and an unspecified number of them had died. Some others had been taken hostage, he said.
If Thursday's death toll is confirmed, it would make it the deadliest day in Ukraine since protests began.